1. Field of the Invention
This invention relates to a heather yarn made of bulked continuous filament yarns having different color and/or dye receptivity and to a process for making such heather yarn.
2. Description of the Prior Art
A continuous filament heather yarn is a yarn consisting of a multiplicity of continuous filaments which are either of different color and/or have a different dye receptivity so that they are capable of being dyed to different colors. The effect of the heather yarn when colored and incorporated into a pile fabric is to display the color of the filaments primarily at the tip of the loop in the pile whether the loop is intact or is cut. The color of the pile fabric then takes on the appearance of the colors appearing at the top of each loop of the heather yarn making up the fabric.
Continuous filament heather yarns have suffered from the disadvantage that the color present at the top of the loops is either (a) the same or very similar color, whereby the pile fabric has the appearance of being made from a single colored yarn as a result of too complete blending of the different colored filament, or (b) too contrasty, i.e., too bold or flashy, which means it is predominantly the colors of the yarns making up the heather yarn that is seen at the tip of the loop in the pile fabric, to give the pile fabric a salt and pepper appearance.
Continuous filament heather yarns of the type (a) are disclosed in Reese, U.S. Pat. No. 3,593,513, wherein filaments of different dye receptivity are co-spun, and continuous filament heather yarns of the type (b) are disclosed in the references to be discussed hereinafter.
U.S. Pat. No. 3,534,540 to Collingwood discloses the making of a heather yarn by the simultaneous crimping of at least two continuous filament yarns having different color or dye receptivity, followed by entangling the crimped filaments and twisting the resultant assemblage to a level of 0 to 2 turns per inch. Unfortunately, the resultant heather yarn when untwisted consists primarily of the component yarns in parallel side-by-side relationship, i.e., the color of one component yarn or the color of the other component yarn predominates, depending on which side of the heather yarn is viewed. Such a heather yarn when incorporated into a pile fabric is too bold in that it is the colors of the component yarns that are primarily seen at the tops of the loops making up the pile. This is seen by reference to Table III of the patent which discloses that only as the twist of the heather yarn increases from 0 to 1.5 turns per inch does the heather increase from not being noticeable to a strong heather. The use of twist in a heather yarn has the effect of breaking up the parallel side-by-side registry of the colored component yarns so that there is a greater opportunity for a different component yarn color to be present at the top of adjacent loops in the pile fabric made from the yarn. The use of twist, however, to accomplish this result gives rise to another disadvantage, namely, if the frequency of the loop length in either a row of loops or a direction transverse thereto corresponds to the frequency of twist, which does occur as a heather yarn is used in a multiplicity of fabrics having different pile height, then the same color can be present at the top of such loops to form a streak in the loop row direction or a line of loops running in the transverse direction to form a chevron in the loop transverse direction.
U.S. Pat. No. 3,724,199 to Armstrong, discloses the different method of making a continuous filament heather yarn, comprising simultaneously drawing side-by-side continuous filament yarns having different dye receptivity, which is followed by an intermingling step to produce a plied yarn. But this process, too, is preferably carried out with a final twisting step and indeed the conventional ring and traveler mechanism 52 shown in the drawing is a twisting device, whereby this process introduces the same disadvantage as does the twisting disclosed in U.S. Pat. No. 3,534,540.
British Patent No. 1,166,247 discloses the making of continuous filament heather yarn by a simultaneous drawing of the component continuous filament yarns except that the next step is either intermingling or twisting. When twisting is the next step, the process is similar to that of U.S. Pat. No. 3,724,199; when intermingling is the next step, the process is similar to that of U.S. Pat. No. 3,534,540. South African Patent Publication 73/3977 discloses a later development to the same assignee as British Patent No. 1,166,247, wherein the continuous filament heather yarn is made by both drawing and crimping the component yarns together, and this is followed by a pair of intermingling steps. In the first intermingling step, the filaments are intermingled within each yarn, and in the second step the two intermingled yarns are brought together for entanglement with one another. In each intermingling step the yarn is under tension as it passed therethrough. In terms of heather, the result of this process is a heather yarn which is too bold, as in U.S. Pat. No. 3,534,540, because the intermingling of the feed yarns prevents them from being blended together.
U.S. Pat. No. 3,846,968 discloses a heather yarn formed eiter from continuous filaments or staple fiber yarn wherein the component yarns are simultaneously passed under tension through a jet intermingling device which exposes the combination of yarns to pulsating air forces which combine the yarns into a single heather yarn comprising high bulk regions alternating with compacted regions, the yarns in the compacted regions being a blend of the yarns making up the heather yarn. The compact regions are apparently to take the place of twist in holding the component yarns together but unfortunately as in the case of twist, the compact regions are regularly spaced which is a disadvantage if their regular spacing corresponds to the amplitude of the loop in a pile fabric.
U.S. Pat. No. 3,811,263 discloses the making of a heather yarn using trilobal cross-section continuous filament especially to accentuate the bold appearance effect of the yarn.